Commit Graph

3 Commits

Author SHA1 Message Date
Nikolai Bozhenov bde9b14c6f Revert of r306525: "Canonicalize clamp of float types to minmax"
llvm-svn: 306815
2017-06-30 10:39:09 +00:00
Nikolai Bozhenov b01e6b5a52 [InstCombine] Canonicalize clamp of float types to minmax in fast mode.
Summary:
This commit allows matchSelectPattern to recognize clamp of float
arguments in the presence of FMF the same way as already done for
integers.

This case is a little different though. With integers, given the
min/max pattern is recognized, DAGBuilder starts selecting MIN/MAX
"automatically". That is not the case for float, because for them only
full FMINNAN/FMINNUM/FMAXNAN/FMAXNUM ISD nodes exist and they do care
about NaNs. On the other hand, some backends (e.g. X86) have only
FMIN/FMAX nodes that do not care about NaNS and the former NAN/NUM
nodes are illegal thus selection is not happening. So I decided to do
such kind of transformation in IR (InstCombiner) instead of
complicating the logic in the backend.

Reviewers: spatel, jmolloy, majnemer, efriedma, craig.topper

Reviewed By: efriedma

Subscribers: hiraditya, javed.absar, n.bozhenov, llvm-commits

Patch by Andrei Elovikov <andrei.elovikov@intel.com>

Differential Revision: https://reviews.llvm.org/D33186

llvm-svn: 306525
2017-06-28 09:26:20 +00:00
Nikolai Bozhenov 4ec1bb6f39 Add tests to document current InstCombine behavior for clamp pattern.
Summary:
This commit adds the tests for clamp pattern as a prerequisite of
D33186 to make the impact of that fix more clear and also to document
current behavior.

Reviewers: spatel, jmolloy

Reviewed By: spatel

Subscribers: n.bozhenov, llvm-commits

Patch by Andrei Elovikov <andrei.elovikov@intel.com>

Differential Revision: https://reviews.llvm.org/D34350

llvm-svn: 306524
2017-06-28 09:22:58 +00:00